Bubbler assembly for blood treating apparatus

ABSTRACT

A BUBBLER ASSEMBLY FOR USE IN A BLOOD TREATING APPARATUS SUCH AS A BLOOD OXYGENATOR FOR FORMING FILMS OF BLOOD IN BUBBLE FORM BY DIRECTING OXYGEN INTO A STREAM OF VENOUS BLOOD TO EFFECTUATE TRANSFER OF OXYGEN TO THE BLOOD FILM AND RELEASE OF CARBON DIOXIDE FROM THE BLOOD FILM. THE BUBBLER ASSEMBLY IS CHARACTERIZED BY AN IMPROVED ARRANGEMENT OF THE BLOOD PASSAGEWAY WHICH IS GENERALLY S-SHAPED IN NATURE; BY A COMPLETELY SMOOTH INTERIOR WHICH ELIMINATES SHARP EDGES; BY AN IMPROVED OUTLET STRUCTURE WHEREBY BLOOD BUBBLES EMPTY OUTWARDLY AND DOWNWARDLY ON A DEFLECTOR PLATE FOR MORE UNIFORM DISTRIBUTION OF BLOOD THROUGH AN ENVELOPING DEFOAMER UNIT; AND BY AN IMPROVED EXTERIOR CONFIGURATION HAVING RECESSED SIDE PORTIONS RELATIVE TO ADJACENT TOP AND BOTTOM STRUCTURE BY MEANS OF WHICH A GREATER PORTION OF THE DEFOAMER SLEEVE IS HELD RELATIVELY SPACED FROM THE BUBBLER STRUCTURE TO ELIMINATE OBSTRUCTIONS TO THE FLOW OF BUBBLES PASSING OUT OF THE BUBBLER UNIT AND TO EXPOSE A GREATER AREA OF THE DEFOAMER SLEEVE TO THE BLOOD.

BUBBLER ASSEMBLY FOR BLOOD TREATING APPARATUS Filed July 22, 1969 y1.971 0. J. BENTLEY ETAL 3 Sheets-Sheet 1 //VVEA/ 7'0?! pwmddgzxzZMm/daa? Z/QZZ 15) Wu 1 44., 9 TOP/V573 BUBBLER ASSEMBLY FOR BLOODTREATING APPARATUS Filed July 22, 1969 D. J. BENTLEY ET AL 3Sheets-Sheet 2 3 sheets sheet 3 BUBBLER ASSEMBLY FOR BLOOD TREATINGAPIARATUS & WW MW Q 5 \ww MW, n uhw Bm k v m g W\ i May 11, i971 FiledJuly .212; 1969 United States Patent O 3,578,411 BUBBLER ASSEMBLY FORBLOOD TREATING APPARATUS Donald J. Bentley, Newport Beach, Calif., andRichard A.

De Wall, Dayton, Ohio; said De Wall assignor to Bentley Laboratories,Inc., Santa Ana, Calif.

Filed July 22, 1969, Ser. No. 843,558 Int. Cl. A61m N03 US. Cl. 23-258511 Claims ABSTRACT OF THE DISCLOSURE A bubbler assembly for use in ablood treating apparatus such as a blood oxygenator for forming films ofblood in bubble form by directing oxygen into a stream of venous bloodto effectuate transfer of oxygen to the blood film and release of carbondioxide from the blood film. The bubbler assembly is characterized by animproved arrangement of the blood passageway which is generally S-shapedin nature; by a completely smooth interior which eliminates sharp edges;by an improved outlet structure whereby blood bubbles empty outwardlyand downwardly on a deflector plate for more uniform distribution ofblood through an enveloping defoamer unit; and by an improved exteriorconfiguration having recessed side portions relative to adjacent top andbottom structure by means of which a greater portion of the defoamersleeve is held relatively spaced from the bubbler structure to eliminateobstructions to the flow of bubbles passing out of the bubbler unit andto expose a greater area of the defoamer sleeve to the blood.

BACKGROUND OF THE INVENTION Field of the invention This inventionrelates to blood treating apparatuses and, more particularly, to abubbler assembly preferably for use with a blood oxygenator.

Brief description of the prior art The present invention is animprovement in the bubbler assembly shown in the copending applicationof Bentley and De Wall entitled Bubbler Assembly for Oxygenator, Ser.No. 601,000 (Series of 1960) filed Dec. 12, 1966. Application Ser. No.601,000 was an improvement upon the bubbler assemblies shown in theRichard A. De Wall Patent No. 3,256,883, issued June 21, 1966 and thepresently copending application of Donald A. Raible, Donald 1. Bentleyand Richard A. De Wall, Ser. No. 465,451, filed June 21, 1965, Bentleyand De Wall application 601,000 has now issued as US. Patent No.3,488,158, and Raible et al., application 465,451 has issued as U.S.Patent No. 3,468,631.

.Prior art cited in the aforementioned Bentley and De Wall applicationSer. No. 601,000 includes the following patents, all from Class 23,Subclass 258.5: Calvin, 293,067; Broman, 3,058,464; De Wall, 3,253,883;Sautter,

All of these patents are directed to oxygenators in their entirety. Inall of these patents, the bubbler portion of the oxygenator is generallya straight tube with a regular exterior periphery. The blood outlet ismerely the distal open end of the tube except in the De Wall Pat.3,253,883, where the outlet comprises plural ports in the wall of thetube with the distal end of the tube wall being closed. In the bloodtreatment art there is a continuing need and desire for thoroughintermixing of blood and oxygen, thorough debubbling of oxygenated bloodand thorough filtering of particles from the blood including theelimination of any accumulated blood fragments. Thorough in- "iceter-mixing of blood bubbles in a bubbler assembly is promoted byavoiding stratification of the blood bubbles. Thorough debubbling anddefoaming is promoted by spreading the emitted blood bubbles so as toexpose the blood bubbles to a wide area of defoaming material in asmooth and continuous flow. Improved filtering is also accomplished byexposing the blood to a greater surface area of the defoaming material.The elimination of blood fibrin and of damage to hemoglobin is promotedby having the blood passageway of a smooth structure free of crevicesand sharp edges or extremely sharp corners.

It is to the provision of these enumerated desired properties and forthe purpose of meeting the above stated need and desire in the art thatthe present invention is directed.

SUMMARY OF THE INVENTION The present invention is directed, in brief, tothe provision of an improved bubbler assembly for a blood treatingapparatus, such as a blood oxygenator.

The best mode currently contemplated by us for carrying out theinvention includes the provision of a one piece plastic molded structurehaving an inlet, three chambers arranged in vertical tandem and incommunication with each other in ascending order, and an outlet at theend of the uppermost chamber remote from the inlet end. Generallyspeaking, in the preferred form the chambers are disposed in a generally'S-shaped array. The structure is preferably formed of a polycarbonateplastic, and it is formed into an integral, single piece by a blowmolding process which results in savings in manufacture over methodswhich adhere a plurality of pieces together.

The interior of the blood passageways defined by the communicatingchambers is free of sharp corners or sharp or raw edges. The bloodoutlet is shaped to direct blood downwardly onto an inclined deflectorplate which is the upper surface of the intermediate blood chamber atthe juncture with the lowest chamber. The sides of the intermediatechamber are recessed relative to the upper and lower chambers. By thisarrangement, the enveloping defoamer sleeve is held spaced from theintermediate portion of the bubbler to minimize obstructions for theemitted bubbles and to afford utilization of a greater portion of thesurface area of the defoamer sleeve.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view ofan oxygenator device of the type in which the bubbler assembly of theinstant invention is intended to be used;

FIG. 2 is an enlarged fragmentary sectional view of the oxygenatingchamber of the oxygenator device shown in FIG. 1 showing the bubblerassembly of this invention in greater detail;

FIG. 3 is a sectional view of the bubbler assembly shown apart from itsintended environmental use in the oxygenator chamber;

FIG. 4 is a vertical sectional view of the bubbler assembly takengenerally along the lines 44 of FIG. 3; and

FIG. 5 is a fragmentary sectional view taken generally along the lines5--5 of FIG. 3.

BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows a bubble typeoxygenator device 10 with which the bubbler assembly of this inventionis intended to be used. As shown, the oxygenator device includes anupper cylindrical chamber 12 (commonly referred to as the oxygenatingchamber), a narrow central chamber 13 (commonly referred to as asettling chamber) and a lower cylindrical chamber 14 (commonly referredto as a heat exchange chamber) and a collecting chamber 18 below theheat exchange chamber. In use, the oxygenator device is preferablysuspended by hooks or other suitable means passing through the apertures20 at opposite ends of the chambers so that in normal operation theangle of the axis of the upper cylindrical chamber relative to thehorizontal is preferably in the range of 35 to 50.

The bubbler assembly 22 of this invention is intended for use in theupper or oxygenating chamber 12 of the oxygenator 10. It is to beunderstood that the bubbler assembly 22 may have suitable use with otherblood treating apparatuses and that the showing of the bubbler assemblywith the oxygenator is only for the purposes of illustrating onepreferred form of use of the bubbler assembly. In use with theoxygenator 10, the bubbler assembly is preferably mounted so that itslongitudinal axis substantially coincides with the longitudinal axis ofthe oxygenating chamber 12.

Generally speaking, the function of the bubbler as sembly is to intermixoxygen gas with incoming venous blood so as to form films of blood inbubble form, which blood bubbles are advanced in an oxygen atmospherethrough the bubbler assembly through an outlet or a plurality ofoutlets. Thus, in the bubbler assembly oxygen is taken on by the venousblood and carbon dioxide carried by such blood is released. The degreeto which the blood is saturated with the oxygen depends significantlyupon the extent to which all of the blood is bubbled, the character ofthe film in the bubbles produced, the time of exposure of the blood filmto the oxygen atmosphere. Preferably the bubbler assembly (as well asthe oxygenator) is formed from a polycarbonate plastic (sold by GeneralElectric under the trademark Lexan). This plastic has been found to bevery suitable for use in blood treating apparatuses in that it is inert,nontoxic, impervious to the passage of gases and liquids, andsterilizable. It further contains no leachable plasticizers which may betraumatic to the blood, and is exceptionally strong and durable towithstand accidental blows or shocks. In addition it has a naturalelectrical surface charge similar in nature to the natural charge of theconstituents of the blood. It is to be understood that while thismaterial has been found preferable for use, any other material whichmeets the same advantageous standards mentioned herein could also besuitably used.

The bubbler assembly 22 is defined by a substantially hollow, elongatedhousing, generally designated 24, which defines an internal chamber,generally designated 26. One end of the chamber is provided with agenerally cylindrical opening 28 which provides an inlet means foradmission of fluids such as oxygen or venous blood.

In one preferred form of use of the bubbler assembly, the open end 28nestably receives an inwardly extending boss portion 30 of the end wallassembly 32 which encloses the forward portion of the oxygenator chamber12. Boss 30 includes a generally frusto-conically shaped Wall member 34which extends from an inlet aperture '36 and flares outwardly to theinterior of the bubbler assembly. Preferably, at least a portion of thewall member 34 is provided with a plurality of small openings orapertures 38 for a purpose to be explained.

A fluid inlet fitting 40 is nested within boss 30 and about inletaperture 36. Inlet fitting 40 includes an oxygen inlet fitting 42 fordirecting oxygen into the interior of the bubbler assembly through theopenings 38 in the frustoconical wall; and a blood inlet fitting 44 fordirecting blood into the interior of the bubbler assembly through theinlet 36 at the reduced end of the frustoconical wall.

The housing 24 and its internal chambers 26 define a continuous closedpassageway leading from the inlet end 28 to an outlet means or opening46 which is remote from the inlet. As mentioned, a thorough intermixingof blood bubbles is most desirable to promote optimum oxygen carbondioxide exchange. The bubbler assembly of this invention is ideallysuited for promoting this 4 thorough intermixing and preventingstratification of the blood bubbles during passage through the bubblerassembly.

The housing 24 is partitioned so that its internal chamber 26 is dividedinto a plurality of chamber segments. A lower chamber segment 48 isdefined by a generally rounded bottom wall 50 and a generally planar topwall 52 and extends from the inlet 30 downwardly and rearwardly awaytherefrom to an upwardly returned rounded end portion 55. The interiorsurface 55a of portion 55 directs fluid upwardly through junctureportion 56 by means of which lower chamber segment 48 is in communication with a vertically adjacent central or intermediate chambersegment 54. Fluid is further directed upwardly and forwardly by theinterior surface 57a of inclined wall portion 57. The exterior surface57b provides a blood spreading surface as will be explained later.

Intermediate chamber segment 54 is defined by a generally planar lowerwall 58 connected by web 58a to wall 52 and a generally planar upperwall 60. Inclined wall portion 57 generally spans wall 60 and roundedend portion 55. A rounded portion 61 of very short radius joins walls 52and 58. Chamber 54 extends from its juncture 56 at the rear incommunication with lower segment 44 to a forward position where it joinswith upper chamber segment 62. The interior surface 63a of upwardlyinclined wall portion 63 directs fluid through juncture portion 64 bymeans of which chamber segment 54 communicates with chamber segment 62.Fluid is returned rearwardly of chamber segment 62 by the interiorsurface 65a of rounded rearwardly returned wall portion 65. Upperchamber segment 62 leads away from its juncture at 64 with centralchamber segment 54 to a rounded end portion 66 and terminates in anopening 46 remote from the inlet 28. End portion 66 is downwardlyreturned relative to the remainder of segment 62 and the interiorsurface 66a thereof provides a deflecting portion adjacent to outletmeans 42 for directing blood toward lower segment 48 and particularly tosurface 57b of inclined wall 57. Upper chamber segment 62 is furtherdefined by a generally planar bottom wall 68 and a generally rounded topwall 70. Bottom wall 68 is joined to wall 60 by web 68a and roundedportion 71 of very short radius.

Thus, blood entering generally through the inlet area 28 will travel aninverted S-shaped path first passing through the lower segment 48,thence being directed upwardly and returned forwardly through thecentral segment 54 and thence being directed upwardly and returnedrearwardly through the upper segment 62 from which it is passedoutwardly through outlet 46. At each bend in the chamber, blood bubbleswill meet generally rounded surfaces and be intermixed. For example, ateach of juncture portions 56 and 64, blood bubbles which were travellingnear the top of the previous chamber segment Will intermix with bloodbubbles that were travelling near the bottom as the blood is directedupwardly and returned in a relatively opposite direction of travel. Bytravelling in this continuous convoluted path, intermixing of the bloodis promoted and Stratification thereof is substantially eliminated.

The lateral extent of lower segment 48 and upper segment 62 is definedby the rounded side edges 72 and 74 of lower segment 48 and 76 and 78 ofupper segment 62. The lateral extent of the central segment 54 isdefined by the generally planar sides 80 and 82. As can be seen best inFIG. 4, sides 80 and 82 are recessed inwardly relative to side portions72, 74 and 76,78. Generally speaking, this provides a longitudinallyextending recess intermediate of the top and bottom of the housing 24 oneither side thereof. When the bubbler 22 is assembled in the oxygenatingchamber 12, it is surrounded by a defoaming sleeve generally indicatedas 84. Typically, the defoaming sleeve includes a polypropylene meshfiber 86 inside of a nylon mesh bag 88. The fiber tends to generallyintimately follow the exterior contour of the bubbler 22. It has beenfound that if the sleeve is too tightly about the exterior of thebubbler, it tends to form an obstruction to the flow of bubbles passingout of the bubbler unit.

With the bubbler of the present invention, the overhang of sides 72, 74and 76, 78 relative to the intermediate sides 80, 82 tends to hold thesleeve 84 spaced outwardly from the intermediate portion of the bubblerassembly as represented by the dotted lines 90 and 92 in FIG. 4. Thisrelationship between the side walls and the sleeve extends throughoutmost of the length of the bubbler and thus, there is free space forblood to flow a substantial distance along the length of the side of thebubbler to insure the free flow of blood and bubbles outwardly of thebubbler and the passage of blood through the defoaming sleeve 84.Further blood passageways are afforded by the spaces 94-96 and 98-100between walls 68 and 60 on each side of web 68a and between walls 58 and52 on each side of web 58a, respectively.

Another feature of the bubbler assembly of the instant invention is thestructure of the outlet 46 and the adjacent spreader plate 57btherebelow. As best seen in FIG. 5, the opening 46 is a large generallyrectangular opening. This opening faces inwardly and downwardly towardsthe blood spreading plate on surface 57b. As the blood bubbles arereturned inwardly and downwardly by the curved surface 66a of deflectingportion 66, they will be fed outwardly through opening 46 and will bespread outwardly toward the defoaming sleeve by deflecting surface 57b.In this area the blood bubbles may pass down the sides of the bubblerand through the defoamer to eliminate bubbles and for suitablefiltering.

It has been found that in some previous bubbler assemblies wherein thenature of the outlet opening was such that it terminated in portions ofdecreasing dimension, these decreased areas of opening, under certain crcumstances of operation, can cause higher velocities through thedischarge opening which can result in the saturation of the defoamingmeans and filter in a localized area adjacent to and above the opening,which is undesirable and reduces the defoaming efficiency of the unit.

With the bubbler assembly of the present invention, the shape of opening46 is such that the likelihood of any clogging occurring therein issubstantially elimlnated. Moreover, the direct proximity of the surface57b immediately below opening 46 encourages smooth blood flow byspreading the blood bubbles outwardly as they are discharged out of theopening 46.

The bubbler assembly of this invention promotes thorough intermixing ofblood and eliminates stratification thereof by directing the bloodthrough an upwardly ascending, generally S-shaped path as described.Throughout the path of travel of the blood, its course is channeled bymeans of rounded or inclined surfaces and no sharp edges or narrowangular recesses or the like are provided in the path of blood flow. Theoutlet opening for the blood is a wide, generally rectangular opening soas to eliminate the possibility of clogging due to the buildup offragmentary matter. The inclined deflector plate below the openingspreads the blood out into thin sheets. From there the blood is free toflow along the sides of the bubbler such as in the relatively recessedareas and outwardly therefrom through the defoaming sleeve with thelikelihood of clogging or backflow eliminated due to the free flow spaceafforded by the recessed configuration.

The foregoing detailed description has been given for clearness ofunderstanding only, and no unnecessary limitations should be understoodtherefrom, as some modifications may be obvious to those skilled in theart.

We claim:

1. A bubbler assembly for use with a blood oxygenator for forming filmsof blood in bubble form by directing oxygen into incoming blood torelease carbon dioxide from the blood and transfer oxygen thereto,comprising: a substantially hollow, elongated housing forming internalchamber means for confining the flow of blood into a pre- 6 determinedpath; inlet means in the housing for directing blood and oxygen into thechamber means from exterior sources; outlet means in the housinggenerally remote from the inlet means for the passage of fluid and gasesoutwardly of the bubbler assembly; and means in the housing for dividingthe internal chamber means so as to define a generally sinous continuousclosed fluid passageway from the inlet means to the outlet means, saidpassageway including a lower segment in communication with the inletmeans, an intermediate segment in communication with said lower segmentand an uppermost segment in communication with the intermediate segmentwith the uppermost segment terminating in said outlet means, said outletmeans facing toward the lower segment.

2. The bubbler assembly of claim 1 wherein the uppermost segmentincludes a deflecting portion adjacent the outlet means positionedrelative to the path of blood flow in the uppermost segment to directblood towards the lower segment as it is discharged through the outletmeans, said bubbler assembly further including a planar blood deflectingsurface below the outlet means positioned transversely to the path ofblood flow exiting the outlet means.

3. The bubbler assembly of claim 2 wherein the deflecting portionincludes a downwardly returned portion of the uppermost segment, withthe outlet means comprising a terminal open end of the uppermost segmentfacing toward the lower segment.

4. The bubbler assembly of claim 3 wherein the bubbler assemblypassageway defines a generally flattened, elongated S-shaped structure.

5. A bubbler assembly for a blood oxygenator comprising: a generallyhollow, elongated housing including an internal chamber with inlet meansin one portion of the chamber for admitting blood and oxygen to the interior thereof and outlet means remote from the inlet means for thepassage of fluid outwardly from the chamber; means defining a continuousclosed passageway for the flow of fluid from the inlet means to theoutlet means, the outlet means terminating in an opening with a planarblood deflector surface on the housing below the outlet means andpositioned generally across the path of blood flow for spreading blooddeposited onto the surface from the outlet means into thin films anddirecting the same away from the outlet means.

6. The bubbler assembly of claim 5 wherein the blood passageway includesplural tandem arranged segments in continuous communication with eachother with the deflector surface being a portion of the housing definingone of the passageways and the outlet opening being closely spaced abovethe blood deflector surface.

7. The bubbler assembly of claim 6 wherein the plural segments include alower and upper segment with the lower segment in communication with theinlet means and with the upper segment including a returned portionfacing toward the lower segment and terminating in said outlet opening.

8. A bubbler assembly for a blood oxygenator comprising: a substantiallyhollow elongated housing having an internal chamber for confining theflow of blood in a predetermined path; fluid inlet means in the housingfor admitting oxygen and blood thereinto; fluid outlet means in thehousing remote from said inlet means; means for dividing the internalchamber into a plurality of segments so as to define a continuous closedpassageway for the flow of fluid from the inlet means to the outletmeans with the exterior walls of the housing including relativelyrecessed portions to provide a means for holding an enveloping defoamersleeve relatively spaced from portions of the bubbler assembly housing.

9. The bubbler assembly of claim 8 wherein the plural segments aregenerally in tandem array including upper and lower segments, with therelatively recessed portions being formed by side wall portions of saidupper and lower segments of the passageway which project laterallyoutwardly beyond adjacent portions of the housing.

10. The bubbler assembly of claim 8 wherein the passageway includes anintermediate segment connected to said upper and lower segment with theintermediate segment having side wall portions spaced inwardly from thelateral extent of the side wall portions of the upper and lowersegments.

11. A bubbler assembly for use with a blood oxygenator for forming thinfilms of blood in bubble form by directing oxygen into incoming blood torelease carbon dioxide from the blood and transfer oxygen thereto,comprising: a hollow housing forming internal chamber means forconfining the flow of blood in a predetermined path; inlet means in thehousing for directing blood and oxygen into the chamber means fromexterior sources; outlet means in the housing generally remote from theinlet means for the passage of fluid and gases outwardly of the bubblerassembly; and means in the housing for dividing the internal chambermeans so as to define a continuous closed fluid passageway from theinlet means to the outlet means,

said passageway including a first elongated segment, a 20 secondelongated, centrally located segment, and a third elongated segment, thefirst segment being in communica- UNITED STATES PATENTS 3,058,46410/1962 Broman 23----258.5 3,087,490 4/1963 Broman 23-258.5 3,112,74612/1963 Gewecke et a1 23-258.5 3,256,883 6/1966 DeWall 23258.5 3,374,0663/1968 Farrant 23-258.5 3,468,631 9/1969 Raible et a1. 23-258.53,488,158 1/1970 Bentley et al. 23-258.5

MORRIS O. WOLK, Primary Examiner B. S. RICHMAN, Assistant Examiner US.Cl. X.R.

